Snap lock cover can



p 1941. A. G. HO PKIN'S 2,257,715

SNAP LOCK COVER CAN Filed June 1, 1938 2 Sheets-Sheet 1 ii. E.

31 l a I ATTORNEYS INVENTOR Amhur G. Hopkins Sept- 30, 1941. A. G. HOPKINS SNAP LOCK COVER JAN 2 Sheets-Sheet 2 Filed June 1, 1938 INVENTOR Avrh u r7 G..Hopkm$ BY Mi? ATTORNEY Patented Sept. 30, 1941 4 SNAP LOCK COVER CAN Arthur G. Hopkins, Maspeth, N. Y., assignor to National Can Corporation, a corporation of Delaware Application June 1, 1938, Serial No. 211,108

6 Claims.

This invention relates to sheet metal containers, and more particularly to a snap lock cover arrangement for use with such containers.

A known typeof can comprises a cylindrical can body having multiple helical threads and cooperating with a cover having mating helical threads. To apply these covers rotationally by hand is expensive and results in some covers being too tight and others being too loose, depending upon the strength and energy of theworker. These covers have also been closed by machinery utilizing a slip clutch mechanism for gripping the cover, but this mechanism is unreliable due to variations in the relative dimensions of the can and cover, and as a result, some covers are applied so tightly as to prevent opening by hand,

while others are so loose that the cover creeps open during shipment.

Another difficulty with the helically threaded cover is that in many packing plants the cover is applied by simply striking the same with a sharp downward blow instead of rotating the same. In some cases the cover is secured too tightly to permit opening, and in others the cover is quite loose, this result depending upon the relative rotational positions of the cover and can when applied, and also depending upon the height of the top edge or curl of the can body relative to the threads thereon.

In an effort to overcome this difliculty, it has been proposed to use a series of Very short or fragmentary helical threads terminated by vertical positive stop ledges which prevent the cover from being rotated more than a small fraction of a revolution. There are substantial spaces between the threads, which together with the extreme shortness of the threads, ensure that the cover and can body when struck together by a blow, must necessarily be in a predetermined rotative relation in order to lock together at all. However, this construction has proved unsuccessful, and in practice it is quite difficult for a worker operating at high speed to locate the covers in exactly proper rotative registration with respect to the can bodies before striking the cover onto the can.

The primary object of my invention is to overcome all of the foregoing diiliculties and disadvantages, and to provide a generally improved can having a snap lock cover arrangement to be used in lieu of the multiple helical thread cans heretofore employed. To this end I accept as a starting point the fact that the cover is likely to be axially struck into locked condition rather than rotated in place, and I have originated a snap lock arrangement designed purposely for this type of engagement. At the same time the user may readily open the cover by rotation in the usual manner.

Further objects of my invention are to so design the can and cover that the cover maybe struck in place on the can in any rotative relation without affecting the locking. engagement therebetween; to devise a locking means such that the cover may be opened by either righthand or left-hand rotation or both; to construct the locking means with such ridges on the can body that the ridges and any beads on the can body may be made in a single operation, thereby ensuring accurate, uniform axial spacing between the locking means and the aforesaid beads; to provide the locking mechanism with detent means which will eifectually prevent accidental rotational release of the cover during shipment or the like; and to provide a stop ledge or the like which will prevent the cover from being struck onto the can body at that particular limited point where the cover and body might not be properly interlocked. v

To the accomplishment of the foregoing and other objects which will hereinafter appear, my invention consists in. the can and cover with snap lock elements and their relation one to the other as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by drawings in which: Y

' Fig. 1 shows a can and cover embodying features of my invention; I

Fig. 2 is an enlarged section taken in the plane of the line 2-4 of Fig. 1;

Fig. 3 is a development of the upper part of the blank out of which the can body of Figs. 1 and 2 is formed;

Fig. 4 is a fragmentary development of a modification embodying detent and stop ledge means;

Fig. 5 is a section taken in the plane of the line 55 of Fig. 4, but with the blank rolled to cylindrical form;

Fig. 6 is a section taken in the plane of the line 6-6 of Fig. 4;

Fig. 7 is a fragmentary development of a modification arranged for release of thevcover by both right-hand and left-hand rotation;

Fig. 8 is similar to Fig. 1, but shows a modifi-v cation;

Fig. 9 is a section taken inthe plane of the line 99 of Fig. 8 and Fig. 10 is explanatory of the opening of the container.

Referring to the drawings, and more particularly to Figs. 1, 2, and 3, the can is here illustrated as comprising a cylindrical can body i2.

It will be understood, however, that the can body itself may vary in shape, although the. neck l4 should be cylindrical. The neck I4 is provided with a circular or non-helical ridge i8, the said ridge being interrupted at a plurality of preferably equidistantly spaced points. The gaps or interruptions in ridge l8 are indicated at l8, and the preferred number is three, this being better than two in order to prevent possible rocking or warping of the cover, and being better than four or more in order to limit the total gap length .to a very small amount relative to the ridge length. The cover 20 has a flange or peripheral wall 22 adapted to be received over the neck [4. Wall 22 is provided with inwardly projecting nibs 24 which are most simply formed by striking the metal of flange 22 inwardly. Nibs 24 are preferably equidistant, and mate with the gaps I8, the

nibs being shorter in peripheral length than the gaps.

To assemble'the can and cover, it is simply necessary to place the cover onneck l4 and to then strike the same downwardly with a sharp blow. The nibs 24 spring over ridge I6 and are locked therebeneath, thus holding the cover in place. The cover may be positioned with considerable freedom and carelessness with respect to the can body, for it has only one limited and easily avoidable point at which the cover is not locked to the can body, this, of course, being when the nibs 24 are in registration with thegaps I8. To release the cover, the user of the can has merely to rotate the cover with respect to the can until the nibs 24 reach the gaps I8, at which time the cover comes free. To facilitate rotation of the cover, it is preferably knurled, as is indicated by the series of vertical projections 26.

The neck I4 is preferably provided not only with discontinuous ridge l8, but also with a continuous ridge 28, said ridge also being circular and non-helical and being disposed somewhat unnecessary in many cases, and the space between the top edge or curl 32 of the can body and the stop 34 of the cover is of no consequence, because the cover is held in one position by the seating of the nibs- 24 between the upper and lower ridges H3 and 28. v

Reverting to Figs. 1 and 3, the upper and lower ridges l6 and 28 are preferably connected at the end of each gap l8 by means of a sloping or helical ridge 86, the said ridge functioning to guide the nibs 24 upwardlyout of-the space or channel 38 between ridges l8 and 28. To a person using the can, the effect is very much.

like the operation of unscrewing the cover from a can provided with multiple helical threads. The cover is simply turned and it comes free'of the and can body is desired, I- prefer to provide each disposed in channel 88 near the gap l8. Detent 48 is preferably less in outward projection than the ridges l6 and 28. Specifically, detent 40 may consist of a short, vertical ridge joining the end of interrupted ridge l8 and the continuous ridge 28, and being about half in height or projection compared to the ridges l8 and 28. With this construction the nibs 24 are readily forced over detent 48 when the cover is purposefully rotated to release the same. However, the detents effectually prevent any creeping or gradual movement of the cover to released position such as might otherwise occur in the course of a shipment involving prolonged periods of vibration of the can.

A second feature found in the modification of Figs. 4 through 6 is the provision of a stop ledge 42 over the gap l8. .Stop ledge 42 is preferably a short horizontal ledge located directly over gap I8 and preferably though not necessarily connected to one end of ridge l8, as is indicated at 44. Ledge 42 is preferably extra large in height or outward projection from the can body. Furthermore, it is preferably provided with an abrupt top surface 46 which is to be contrasted with the preferably sloping or gradually flaring top surface 48 provided on ridge l6. Because of theabruptness of ledge 42 and because of its extra high projection, it effectually stops the nibs 24 from being forced thereover should someone attempt to apply the cover to the can body by simply striking the same downwardly with the nibs disposed at the gaps l8. In this way the construction is made foolproof, for even that small or limited point at which the cover might be applied to the can body without interlocking the same, ,i s eliminated by preventing attempted assembly at that point. The stop ledge 42 is, of

course, spaced upwardly or axially from ridge IS an amount sufficient to provide an adequate escape passage 50 therebetween through which the nibs 24 readily pass as the cover is unscrewed from the can body.

Still another modification of the invention is illustrated in Fig. 7, referring to which it will be seen that the upper or interrupted ridge 52 is provided with a gap 54 of greater length, while the lower ridge 56 is provided at gap 54 with a pair of oppositely upwardly sloping ridges or guide ply disposing the sloping or helical ridge 38 in opposite direction at the opposite side of gap l8. The arrangement of Fig. 7 is simply a combination of both right-hand and left-hand release.

Referring now to Figs. 8, 9, and 10, I illustrate a modification of the invention, the most import-- ant difference in which arises from the fact that the peripheral spacing of the nibs is different from the spacing of the gaps. A simple and preferable way to do this is to provide the can body 64 with a diflerent number of interruptions downwardly into locking engagement with the can body regardless of the rotational relation between the cover and can body. There is no dead spot at which the cover will not be locked in position. Even if one of the nibs 68 comes directly over one of the interruptions 66, the other three nibs will be out of registration with the other I two interruptions and will be locked beneath interrupted ridge 12.

when the cap is unscrewed or released, one

of the nibs reaches one of the sloping ridge con-' nections '1 4 sooner than the others, and the cover is thereby tilted, as shown in Fig. 10. With the arrangement of Fig. 1,,the cover is lifted in level position, whereas with the construction of Fig. 8-, the cover is tilted but it nevertheless comes free of the can body by a simple turning movement without any noticeable difference in operation other than that the cap may have to be turned through a somewhat greater are before being entirely freed. Ordinarily, the cover is freed as soon as two of the nibs have passed out of the channel between the ridges. In reality, this is an advantage rather than a disadvantage in that it helps prevent the possibility of accidental loosening of the cover.

The modification of Figs. 8 through 10 differs in another respect, namely, in the omission of the body bead 33. The lower ridge ii serves a dual function, first in defining the channel in which nib $8 is received, and second in acting as a bead which engages the interior of-flan'ge ll of the cap Just within the rolled edge 80, as is clearly shown in Fig. 9.

Another difference illustrated in Figs. 8 through 10 is the production of a good seal between the cover and body without using a resilient liner. The cover III is so shaped and dimensioned in the region of the point 82 relative to the rolled upper edge 84 of the can body, that the parts are brought into reasonably good sealing relation under the tension provided by the fit of nibs 68 beneath ridge I2.

It is believed that the construction and operation of my improved can with snap lock cover, as well as the many advantages thereof, will be apparent from the foregoing detailed description. The cover may be applied to and securely locked on the can by simply striking the same downwardly over the neck of the can. This may be done by hand or by machine, and in the latter case, only a small straight ram is needed, which is relatively inexpensive compared to slip clutch coverrotating machinery. The tightness or tension the most convenient and preferable one.

long uninterrupted portions of the ridge, thus ensuring proper locking relation therebetween when the cover is struck downwardly. Even this limited free point is avoided by using a different spacing for a number of nibs and interruptions, as in Fig. 8. The can may be arranged for either right-hand or left-hand release of the cover or for both, the cover being released by simple rotation similar to that used when dealing with helical threads. Detents may be provided to prevent accidental creeping or release of the cover during shipment. Stop ledges may be provided to prevent the cover from-being assembled with the can at even that single limited point where they would not interlock. A tight seal with the can is obtainable, with or without a resilient liner, and the tension of the seal is dependable and uniform because of the non-helical nature of the ridges. Even where no seal is required or provided, looseness or vibration of the cover relative to the can body is effectually prevented by use of a lower as well as an upper ridge between which the nibs are snugly received. In this way no dimculty arises-by reason oi variations in axial dimension between the top edge or curl of the can and the ridges. The cover whether applied manually or by machine can not be locked so tightly as to prevent manual release by rotation of the cover.

It will be understood that in all forms of the invention the cover may be arranged to ilt inside instead of outside of the can body, and further, that the ridges may be formed on the cover and the nibs on the neck of the can body. although the illustrated arrangement is believed It will therefore be apparent that while I have shown and described my invention in preferred forms, many changes and modifications may be made in the structures disclosed without departing from the spirit of the invention defined in the following claims.

I claim:

1. A sheet metal can and a snap'lock cover therefor, said can comprising a, cylindrical can body with a curled upper edge and two circular or non-helical ridges struck outwardly from said can body near the upper end thereof, the lower of said ridges being continuous and the upper of said ridges being discontinuous or interrupted at a plurality, say, three, points to form gaps, said cover being formed of a single piece of sheet metal dished to form a peripheral flange, said with which the cover is locked on the can is uniform, for the locking ridges are circular or nonhelical. The position of the cover rotationally place the' nibs somewhere along the relatively flange being knurled to facilitate turning thereof 4 and being struck inwardly at another plurality of, say four, points to form nibs adapted to be forced over the upper ridge and .to fit between the upper and lower ridges and to thereby hold the cover in place, the spacing between the gaps or interruptions in the upper ridge being different from the spacing between the points or nibs, the width of the gapsbeing at least equal to the peripheral dimension of the'nibs, the upper ridge being joined by means of a helically sloping ridge to the lower ridge at one end of each of the gaps or interruptions in the upper ridge, in order to guide the nibs upwardly out of the space between the ridges when the cover is rotated relative to the can body.-

2. A sheet metal can and a snap lock cover therefor, said can comprising a can body with a circular or non-helical ridge on said can body near the upperend thereof, said ridge being interrupted at a plurality of points to form gaps, said cover having a peripheral flange and said flange being provided at a plurality of points with inwardly projecting nibs adapted to be forced over the aforesaid ridge in order to hold the cover in place, and sloping means on the body at the interruptions to lift the nibs and cover upwardly upon relativerotation of the can body and cover, the width of the gaps being at least equal to the peripheral dimension of the nibs, the number of interruptions on the body being slightly different from the number of nibs on the cover, and the spacing between the interruptions on the body being different from the spacing between the nibs on the cover, thereby avoiding registration of the nibs and the interruptions when forcing the nibs over the ridge,

3. A sheet metal can and a snap lock cover therefor, said can comprising a can body with two circular or non-helical ridges on said can body near the upper end thereof, the lower of .said ridges being continuous and the upper of ridge and to fit snugly between the upper and lower ridges and to thereby hold the cover in place, the width of the gaps being at least equal to the peripheral dimension of the nibs, the upthe nibs on the cover, thereby avoiding registration of the nibs and the interruptions when forcing the nibs over the upper ridge.

4. A sheet metal can and a snap lock cover therefor,- said can comprising a can body with two circular or non-helical ridges on said can body near the upper end thereof, the lower of said ridges "being continuous and the upper of said ridges being discontinuous or interrupted at three equally spaced points, said cover having a peripheral flange, said flange being provided at four equally spaced points with inwardly directed nibs adapted to be forced over the upper ridge and to fit snugly between the upper and lower ridges and to thereby hold the cover in place, the upper ridge being joined by means of a helically sloping ridge to the lower ridge at one end of each of the gaps or interruptions in the upper ridge, in order to guide a nib upwardly out of the space between the ridges when the cover is' rotated relative to the can body.

5. A sheet metal can and-a snap lock cover therefor, said can comprising a cylindrical can body with a curled upper edge and a circular or non-helical ridge struck outwardly from said can body near the upper end thereof, said ridge being interrupted at a plurality, say three, equidistantly spaced points, said cover being formed of a single piece of sheet material dished to form a peripheral flange, said flange being struck inwardly at a different plurality, say four, equidistantly spaced points to form nibs adapted to be forced over the ridge in order to hold the cover in place, said nibs being shorter in a peripheral direction than the gaps in the ridge.

6. A sheet metal can and a snap lock cover therefor, said can comprising a can body with a circular or non-helical ridge on said can body near. the upper end thereof, said ridge being interrupted at more than two points to form gaps in said ridge, said cover having a. peripheral flange and said flange being provided at more than two points with inwardly projecting nibs adapted to be forced over the aforesaid ridge in order to hold the cover in place, the width of the gaps being approximately equal to the peripheral dimension of the nibs, the peripheral space between any two adjacent gaps on the body being different from the peripheral space between any two adjacent nibs on the cover, thereby avoiding registration of the nibs and gaps when forcing the nibs over the ridge.

ARTHUR G. HOPKINS. 

